After being fired from his job as school janitor, Lucky shows up at Neptune High threatening Gia Goodman and is killed by security.
Keith thinks that Lucky might have planted bombs in Goodman's house and informs Sheriff Lamb, who finds a bomb under Goodman's car identical to the one that was on the bus.
Veronica finds an anonymous email entitled "Kill incorporation or else" on Goodman's computer that has a recording of two boys saying that he is a child molester. Veronica figures out that the two boys in the recording were Peter Ferrer and Marcos Oliveres, two boys who died in the bus crash and were also on Goodman's Little League team.
Lamb goes to arrest Goodman, but he's already gone.
Veronica walks out of her final test to witness the Aaron Echolls murder trial verdict, ruining her chances of winning the Kane Scholarship (which, in turn, prevents her from going to Stanford).
Aaron Echolls is found not guilty of Lilly Kane's murder.